Treatment of hydrocarbon oil



Jan., 7; N36. v. sTAPLu-:TN

vTREIAIMENV'I OF HYDROCARBON OIL Filed July 15, 1953 4 lNvN-roR VICTOR sTAPu-:TON www i# M ATTORNEY Patented Jan. 7, 1936 UNITED STATES PATENT OFFICE Victor Stapleton, Port Arthur, Tex., assigner to The Texas Company, New York, N. Y., a corporation of Delaware Application July 15, 1933, Serial No. 680,510

Claims.

This invention relates to the treatment of hydrocarbon oil, and more particularly to the pyrolytic conversion of relatively high-boiling hydrocarbon oils to oils of lower boiling points, such as gasoline.

My invention represents an improvement on, and has an especial utility with respect to, an operation of the so-called low-liquid-level type, wherein a charging oil comprising residual petroleum constituents is introduced into an enlarged reaction zone maintained at cracking temperature and under superatmospheric pressure supplied with hydrocarbon vapors at a cracking temperature, and wherein separation of liquid and vapors occurs. In this type of operation, liquid is withdrawn from the enlarged cracking zone at a rate adequate to prevent accumulation of liquid therein, and vapors may be separately removed and fractionated to recover the desired final gasoline distillate and a heavier fraction comprising a clean gas oil condensate. The latter is heated to a relatively high cracking temperature While in transit through a conlined heating zone and the resultant cracked vapors are delivered into the enlarged reaction zone as aforesaid.

My invention has for an object the provision of an "tiproved process for accomplishing the conversion of relatively high-boiling hydrocarbon oils to oils of lower boiling points, wherein 'a reduced crude or a dirty gas oil, or a mixture thereof, may be cracked in such manner as to make possible the conversion thereof to gasoline of high anti-knock value, while avoiding diiiiculties due to carbon deposition or coke formation.

My invention has for a further object the provision of an improved method whereby the fractionation and recovery of valuable light distillatefrom the products resulting from the cracking of hydrocarbon oil may be facilitated and this aspect of the invention is not necessarily limited to the low liquid level method of cracking.

My invention has for further objects such additional improvements in operative advantages and results as may hereinafter be found to 0btain.

In its preferred embodiment, my invention contemplates, in an operation of the character set forth hereinabove, that is to say, a low-liquidlevel operation, the supplying of fresh charging stock either in a heated or unheated condition to the lower portion of the reaction vessel from which liquid is removed at a rate adequate to prevent accumulation of liquid within the reaction zone, and the delivery of the liquid thus.

withdrawn to a zone of lower pressure wherein it is ashed to vaporize lighter constituents thereof in vapor form, the charge oil introduced into the reaction zone passing therethrough at a very rapid rate and remaining in the reaction 5 zone for an extremely short period of time. In order to assist the vaporization in the low-pressure flashing zone a portion of the vapors liberated in the enlarged reaction zone may preferably be delivered with the liquid to the ashing 10 zone. This delivery of vapors may be accomplished by bleeding oli a portion of the vapors passing to the high-pressure fractionating zone and-leading them into the lowrpressure flashing zone, or by increasing the rate of withdrawal of the liquid from the lower portion of the reaction zone to such extent that a-portion of the vapors liberated within the reaction zone will pass out with the liquid and be delivered with the withdrawn liquid to the low-pressure ashing zone.

The vapors liberated in the low-pressure flashing zone may be fractionated to recover therefrom a clean condensate suitable for high temperature cracking, which may be delivered to the aforesaid heating Zone, as well as lower-boiling, normally liquid constituents, which are suitable for use as a reflux in either the low-pressure fractionating zone or the high-pressure fractionating zone, or both. The invention contemplates that the gases and vapors remaining uncondensed in the low-pressure zone may be compressed and commingled with vapors leaving the high-pressure fractionating zone and the commingled products passed to a condenser wherein condensation of gasoline is effected.

The gasoline thus condensed may be subjected to stabilization under the influence of heat exchange with hot products from one or both of the aforesaid fractionating zones. Thus, the separated gasoline may be passed into indirect heat-exchange relationship with vapors leaving the high-pressure fractionating zone, and may then be delivered to a stabilizer or reflux distillation column wherein further heating may be effected by -means of indirect heat-exchange with hot gas-oil condensate from the high-pressure fractionating zone, the low-pressure frac-l tionating zone, or both.

In the stabilizing zone, a volatilization ofthe lighter constituents of the raw gasoline is effected, the normally liquid constituents being condensed and returned. The gas oil employed for supplying heat to the stabilization zone by indirect heat exchange may after such use be returned as a reux cooling medium to one or both of the aforesaid fractionating zones.

In order that my invention may be more clearly set forth and understood, I now describe, with reference to the drawing accompanying andl forming part of this specication, a preferred manner in which my invention may be practiced and embodied. In this drawing:

The single gure is a more or less diagrammatic View of aparatus for effecting the conversion of relatively high-boiling hydrocarbon oil to oils of lower boiling points in accordance with my present invention.

Referring now to the drawing, a suitable charging stock, for example a reduced crude, a heavy or dirty gas oil, or a mixture of these, is introduced from a suitable source (not shown) through a conduit I by means of the pump 2 to a heat exchange coil 3 located in the upper portion of a fractionating tower 4. By means ofa valve 5 located in the conduit I and a by-pass 6 having a valve 'I and communicating between the conduit I and a conduit 8 receiving oil from the coil 3, the proportion of the charging stock passed through the coil 3 may be varied to give the desired cooling effect in the fractionating tower 4. Or, if so desired, as when some other means is provided for cooling the fractionating tower 4, the valve 5 may be closed and the entire flow of charging stock may then be delivered from the conduit I through the by-pass 6 to the conduit 8. In the preferred instance, the charging stock after having been preheated to a temperature of, for example 450 F. in the coil 3, passes through the conduit 8 wherein is located a valve 9, and enters the bottom of an enlarged vertically-disposed cracking vessel or reaction chamber II. The chamber II may be maintained under a pressure of, for example from 200 to 600 pounds per square inch or higher, and receives hot cracked products from a coil I2 located within a furnace I3, which products pass from coil I2 through a transfer line I4 preferably communicating with the lower portion of the reaction chamber II. If desired, all or a portion of the charging stock may be delivered from the conduit il, through a branch conduit I5 having a valve i 8, to the transfer line I4, wherein it is commingled with the hot cracked products passing from the coil I2 to the reaction chamber II.

Within the reaction chamber II, a separation of liquid and vapors occurs, the separated liquid, including residual constituents of the charging stock which are not vaporized by contact with the hot cracked products from the coil I2, being withdrawn from the bottom ofthe reaction chamber Il through a conduit I'I having a valve I8 at a rate adequate to prevent accumulation of liquid within the reaction chamber II. The liberated vapors pass upward through the reaction chamber I I under cracking temperature and pressure and are withdrawn through xa vapor line I9 leading to the fractionating tower 4. The fractionating tower 4 may be provided interiorly with suitable plates or bubble trays 2l, which may be of conventional type, for the purpose of asisting in the fractionation of the vapors passing therethrough, and is preferably maintained under a pressure approximating that maintained within the reaction chamber il, although a somewhat lower but still elevated superatmospheric pressure, for example pounds per square inch, may be maintained Within the fractionating tower 4.

Within the fractionating tower 4, the vapors introduced through the vapor line I9 arepartially condensed and fractionated to separate out constituents heavier than gasoline, that is to say gas oil constituents, and the gas oil condensate thus obtained, being clean in character, represents a suitable charging stock for a hightemperature cracking operation.

Accordingly, this clean condensate stock is withdrawn from the bottom of the fractionating tower 4 through a line 22 having a valve 23, and is then passed in whole or in part through conduit 24 wherein is located a pump 25 to the cracking coil I2.

'I'he oil is heated in the coil I2 to a high cracking temperature, such for example as of the order of 900 F. or 1000 F. and the flowing oil is preferably subjected to a high rate of cracking per pass in the coil, such for example as a rate of about 20% or even higher.

The highly heated products from the coil I2 are discharged into the reaction chamber II into which the residual charging stock is also introduced and wherein a cracking temperature above 850 F., and preferably approximately within a range of,\870 F.930 F., is maintained. As my invention"contemplates the introduction of the charging stock into the. lower or lower-most portion of the reaction chamber I I and the rapid removal of liquid from the latter, it will be obvious that the time of contact of the liquid component of the charging stock within the reaction chamber II is extremely short, although the reaction on vapor constituents in the reaction cham- `'ber is prolonged. I have found this advantageous in that it provides for the substantially complete elimination of carbondeposition within the reaction chamber II. The liquid oil which is rapidly withdrawn from the reaction chamber II is 'passed immediately into a low pressure vaporizing or flash chamber 3D, preferably comprising a section or compartment of a tar stripper indicating generally by the reference numeral 3| and having a fractionating section 32. It will be obvious to those skilled in the art, however, that the sections 30 and 32 may comprise independently constructed units wherever this is desired.

By means of the valve I8, the liquid flowing to the section 30 of the tar stripper 3l is materially reduced in pressure, the pressure maintained within the section 30 being as low as from atmospheric pressure up to about 50 pounds per square inch in a typical instance. It will be understood, however, that the exact pressure maintained depends upon the character of the charging stock, the extent of distillation desired, and other factors, and the specific pressures given herein, while typical, are set forth merely by way of example.

In the low-pressure section 30 a flashing or autogenous distillation of the liquid introduced thereto takes place, the lighter constituents of the liquid being vaporized and passing through a conduit 33 into the lower portion of the tar stripper fractionatingsection 32, while the unvaporized residual liquid portions are withdrawn through a conduit 34 having a valve 35 and preferably leading to a cooler 36. In order to assist the distillation in the chamber 3Q a portion of the vapors passing through the vapor line I9 may be passed to the tar stripper 3 I as through a branch conduit line 37 having a valve 38 thence through the conduit VI to the tar stripper.

As an alternative method of procedure, the .withdrawal of liquid from the reaction chamber -or Vthrough a conduit B4 and one or more of a plu- .I I may be regulated to such extent as to avoid the maintenance of any liquid level at all Within the ulated to such a rate that the pipe |1 serves toV convey not only liquid but also a regulated amount of vapors into the tar stripper 3|.

According to my invention, however, whether the vapors delivered to the tar stripper 3| pass thereto through the pipe il or through the vapor line 31, these vapors will in all instances constitute a portion, and preferably a small portion,

CJD

of the vapors liberated in thereaction chamber the greater portion of the liberated vapors passing to the high-pressure fractionating tower 2|.

By reason of this passage of unfractionated vapor directly to the tar stripper 3| for the purpose of assisting in the distillation of the residual liquid withdrawn from the reaction charnber and delivered to the tar stripper 3|, the

vapors passing through the line 33 into the fractionating section 32 of the tar stripper 3| will ordinarily contain considerable quantities of light constituents including gasoline constituents, and I therefore provide means for effecting fractionation and recovery of these constituents in an efcient manner.

As in the case of the fractionating tower 4, the tar-stripper fractionating section 32 may be interiorly provided with plates or trays 4| for assisting in the fractionation of the vapors passing therethrough. By means of cool reiiux oil introduced through a conduit 42, or by means of cooling effected in any other suitable manner, the vapors passing upward through the fractionating section 32 are subjected to partial condensation and fractionation to condense the heavier constituents therefrom. The condensate ordinarily comprises a gas oil, and is withdrawn from the bottom of the fractionating section 32 through a conduit 43 wherein is located a pump 44. A portion of this gas oil may be passed through a branch conduit 45 having a valve 46 to the cooler 4l, from which it is returned to the fractionating section 32 through a line 43. This returned portion of the gas oil serves as a reflux for the fractionating section 32. The remaining portion, or it may be, all of the condensate recovered in the fractionating section l32 passes through a conduit 5| having a valve 52, and may be delivered by means of a. branch conduit 53 having a valve 54 to the inlet side of the pump 25, or, as in the preferred instance, may be delivered through a branch conduit 55 having a f valve 55 to the high-pressure fractionating tower 4 for further treatment therein.

The vapors remaining uncondensed at the top of the fractionating section 32, will ordinarily comprise largely gasoline or naphtha constituents and may include some intermediate constituents within the kerosene or gas oil boiling ranges and these vapors pass through a vapor line 51 to a condenser 58; the mixtureV of condensate .and uncondensed gases and vapors passing to a gas separator 59 which may be maintained at a pressure of 50 lbs. per square inch or less. From the latter, condensate is withdrawn through a conduit 6| having a valve 52 and a pump E3, and may be passed either through the line 42 to the upper portion of the tar stripper fractionating section 32 n rality of valved refiux inlets to the high-pressure fractionating tower 4. Valves 56 and 61 are provided in the conduits 42 and 54 for regulating the proportions of condensate delivered to the fractionating section 32 and the fractionating tower 4, respectively.

The vapors remaining uncondensed at the top of the high-pressure fractionating tower 4 pass through avvapor line 68 to a heat exchanger 69 and a condenser 19, from which condensate and uncondensed gases and vapors are delivered through a conduit 'il to a gas separator 12 which may be maintained under a superatmospheric pressure as from l0 to 100 pounds per square inch. Due to the relatively low pressure maintained in the gas separator 59, the gases separated therein are wet in character, that is to say they are saturated with valuable normal liquid constituents to an Aextent which does not obtain as to the gases separated in the relatively high-pressure gas separator T2. The wet gas from the separator 59 is therefore delivered through a line 13 by means of a compressor 14 to the stream of vapors passing from the fractionating tower 4 to the condenser 10. It is thus possible to effect a substantially complete separation of valuable gasoline constituents from the vapors leaving the tar stripper 3|, while providing a dry gas at a pressure adequate to insure its delivery into the usual gas main. This dry gas is withdrawn from the separator 'i2 through a gas line 15 having a valve 'i6 and leading to the gas main Due to the pressure maintained within the gas separator l2, however, the gasoline collecting therein may require stabilization for the removal of gaseous or very light constituents therefrom. In the preferred instance, this gasoline is therefore passed through a conduit 8| having a valve 82 to the heat exchanger 89, wherein it comes into indirect heat-exchange relationship with the hot vapors leaving the high-pressure fractionating tower 4. In a typical instance, the temperature of the vapors leaving the tower 4 may be 470 F., this being sufcient to bring the gasoline which leaves the heat exchanger S9 through a conduit 83 to a temperature of .approximately 400 F., at which temperature the preheated gasoline is delivered to a stabilizer 85.

The stabilizer 85 is preferably interiorly provided with suitable plates or trays 85. Vapors remaining uncondensed at the top of the stabilizer 85 pass through a vapor line 81 to the condenser 88, the condensate and gases passing through a line 89 to a gas separator 9|. From the latter, the total condensate is returned through a conduit 92 having a valve 93 and a pump 94 to the upper portion of the rectifying column 85, while any uncondensed gases pass through a gas line 95 having a valve 96 to the gas main The stabidenser 10 and the removal of uncondensed gases .from the separators 12 and 9|.

For the purpose of assisting in the stabilization of the gasoline delivered to the stabilizer 85, a portion of the hot gas-oil stream delivered by the pump 25and ordinarily emanating from the bottom of the fractionating tower 4, may be passed through a conduit i having a valve |02 to aV reboiler coil |03 located within the base of the stabilizer 35.V The partially cooled gas oil, after heat exchange with the gasoline within the stabilizer 85, passes from the'coil |03 through a conduit iM and is returned through the conduits 5l and 55 to the fractionating tower 4, together with gas oil withdrawn from the tar-stripper fractionating section 32.

The stabilized gasoline collecting in the bottom of the stabilizer 85, after contact with the reboiler coil |53, is withdrawn from Ythe stabilizer 85 through a conduit i535, and passes to a cooler |06 from whichit is withdrawn through a conduit H31 having a valve |88 to storage or treating equipment.

As illustrated in the drawing, the reaction chamber H, the fractionating tower 4, tar stripper 3i, stabilizer 35 and the gas separators 59, '12, and Si, may be provided with floats or other suitable devices for controlling or assisting in the control of the liquid levels therein, such devices being well known in the art and requiring no detailed description.

While I have described my invention hereinabove with respect to a specific example or examples, it will be understood by those skilled in the art that my invention is not limited to the details of the illustrative example or examples, but may variously be practiced and embodied within the scope of the claims hereinafter made.

I claim:

1. The process of obtaining gasoline from relatively high-boiling hydrocarbon oil which comprises: heating said oil to a cracking temperature While in transit through a heating Zone, discharging the resultant products into a separating zone and separately removing vapors and residual liquid therefrom; passing at least a portion of said vapors through a high-pressure fractionation zone to effect a condensation of constituents heavier than gasoline; flashing said residual liquid into a zone of lower pressureto liberate lower-boiling constituentsk in vapor formV and passing the liberated vapors through a relatively low-pressure fractionation zone to condense constituents heavier than gasoline; removing uncondensed vapors from said low-pressure fractionation zone, cooling them to effect a condensation of gasoline constituents, and separating gasoline condensate from the vapors and gases remaining uncondensed in a low-pressure separating Zone; compressing said remaining vapors and gases and commingling them under the increased pressure with vapors leaving said highpressure fractionation zone; cooling the combined vapors and gases under a pressure in excess of that of said low pressure separatingY zone to effect a condensation of gasoline constituents; and separating the gasoline condensate thereby obtained from the remaining gases under a pressure materially above atmospheric.

2. The process of obtaining gasoline from relatively high-boiling hydrocarbon oil which comprises: introducing said oil into a distillation Zone supplied with hydrocarbon vapors and maintained under superatmospheric pressure and at a cracking temperature; separately removing vapors and residual liquid from said distillation zone; passing at least a portion of said vapors through a high-pressure fractionating zone to effect a condensation of constituents heavier than gasoline; passing condensate from said fractionating Zone through a heating zon e,lhe ating it while in transit therethrough to a cracking temperature, and discharging the resultant products into said distillation zone; flashing residual liquid from said distillation zone into a zone of lower pressure to liberate lower-boiling constituents in` vapor form and passing the liberated vapors through a relatively low-pressure fractionation zone to condense constituents heavier than gasoline; removing uncondensed vapors from said low-pressure fractionation zone, cooling them to effect a condensation of gasoline constituents and separating gasoline condensate from the vapors and gases remaining uncondensed in a low pressure separating zone; compressing said remaining vapors and gases and commingling them under the increased pressure with vapors leaving said high-pressure fractionation zone; cooling the combined vapors and gases under a pressure in excess of that of said low pressure separating zone to effect a condensation of gasoline constituents, and separating the gasoline condensate thereby obtained from the remaining gases under a pressure materially above atmospheric.

3. The process of obtaining gasoline from relatively high-boiling hydrocarbon oil which comprises: introducing said oil into a distillation zone supplied with hydrocarbon vapors under superatrnospheric pressure and at a cracking temperature; separately removing vapors and residual liquid from said distillation zone; passing at least a portion of said vapors through a high-pressure fractionating Zone to effect a condensation of constituents heavier than gasoline; passing condensate from said fractionating zone through a heating zone, heating it while in transit therethrough to a cracking temperature, and discharging the resultant products into said distillation zone; flashing residual liquid from said distillationzone together with aV portion of the vapors from said distillation zone into a zone of lower pressure to liberate lower-boiling constituents in vapor form and passing the liberated vapors throughV a relatively low-pressure fractionation zone to condense constituents heavier than gasoline; removing uncondensed vapors from said low-pressure fractionation Zone, cooling them to effect a condensation of gasoline constituents and separating gasoline Vcondensate from the vapors and gases remaining uncondensed; compressing said remaining vapors and gases and commingling them with vapors leaving said high-pressure fractionation zone; cooling the combined vapors and gases to effect a condensation of gasoline constituents, and separating the gasoline condensate thereby obtained from the remaining:

gases under a pressure materially above atmospheric.

4. The process of obtaining gasoline from relatively high-boiling hydrocarbon oil which comprises: heating said oil to a cracking temperature H Yconstituents in vapor form, and passing the liberated vapors through'a relatively low-pressure fractionation zone to condense constituents heavier than gasoline; removing uncondensed vapors from said low-pressure fractionation zone, cooling them to effect a condensation of gasoline constituents, and separating gasoline condensate from the vapors and gases remaining Yuncondensed in a low-pressure separating zone; compressing said remaining vapors andY gases and commingling them under the increased pressure with vapors leaving said. high-pressure fractionation zone; cooling the combined vapors and gases under a pressure in excess of that of said low-pressure separating zone to effect a condensation of gasoline constituents and separating the gasoline condensate thereby obtained from the remaining gases under a pressure materially above atmospheric; and subjecting the separated gasoline condensate to reflux distillation under the influence of heat exchange with hot products from said high-pressure fractionating zone.

5. The process of obtaining gasoline 'from relatively high-boiling hydrocarbon oil which comprises: heating said oil to a cracking temperature While in transit through a heating Zone, discharging the resultant products into an enlarged separating zone, and separately removing vapors and residual liquid therefrom; passing at least a portion of said vapors through a high-pressure fractionation zone to effect a condensation of constituents heavier than gasoline; flashing said residual liquid into a Zone of lower pressure to liberate'lower-boiling constituents in vapor form and passing the liberated vapors through a relatively low-pressure fractionation zone to condense constituents heavier than gasoline; removing uncondensed vapors from said low-pressure fractionation zone, cooling them to effect a condensation of gasoline constituents and separating gasoline condensate from the vapors and gases remaining uncondensed in a low-pressure separating zone; compressing said remaining vapors and gases and commingling them under the increased pressure with vapors leaving said highpressure fractionation zone; cooling the combined vapors and gases under a pressure in excess of that of said low-pressure separating zone to effect a condensation of gasoline constituents and separating the gasoline condensate thereby obtained from the remaining gases under a pressure materially above atmospheric; lsubjecting the separated gasoline condensate to heat exchange with hot vapors and condensate from said high-pressure fractionating zione to distill the same, and condensing and reuxing normally liquid constituents thereby vaporized.

6. The process of obtaining gasoline from relatively high-boiling hydrocarbon oil which comprises: heating said oil to a cracking temperature while in transit through a heating zone, discharging the resultant products into a separating zone, and separately removing vapors and residual liquid therefrom; passing at least a portion of said vapors through a high-pressure fractionation zone to eiect a condensation of constituents heavier than gasoline, flashing said residual liquid into a zone of lower pressure to liberate lowerboiling constituents in vapor form, and passing the liberated vapors through a relatively lowpressure fractionation zone to condense constituents heavier than gasoline; removing uncondensed vapors from said low-pressure fractionation zone, cooling them to effect a condensation of gasoline constituents, and separating gasoline condensate from the vapors and gases remaining uncondensed in a low-pressure separating zone; compressing said remaining vapors and gases and commingling them under the increased pressure With vapors leaving said high-pressure fractionation zone; cooling the combined vapors and gases under a pressure in excess of that of said low-pressure separating zone to effect a condensation of gasoline constituents, and separating the gasoline condensate thereby 'obtained from the remaining gases under a pressure materially above atmospheric; and stabilizing the separated gasoline condensate by means of indirect heat exchange with hot vapors leaving said high-pressure fractionating Zone.

7. The process of obtaining gasoline from relatively high-boiling/hydrocarbon oil which com- 5 prises: heating said oil to a cracking temperature While in transit through a heating zone, discharging the resultant products into a separating zoneI and separately removing vapors and residual liquid therefrom; passing atleast a portion of said vapors through a high-pressure fractionation zone to effect a condensation of constituents heavier than gasoline, flashing said residual liquid into a Zone of lower'pressure to liberate lower-boiling constituents in vapor form, and passing the liberated vapors through a relatively low-pressure fractionation Zone to condense constituents heavier than gasoline, removing uncondensed vapors from said low-pressure fractionation zone, cooling them to effect a condensation of gasoline constituents, and separating gasoline condensate from the vapors and gases remaining uncondensed in a low-pressure separating zone; compressing said remaining vapors and gases and commingling them under the increased pressure with vapors leaving said high-pressure fractionation zone; cooling the combined vapors and gases under a pressure in excess of Ythat of said low-pressure separating Zone to effect a condensation of gasoline constituents, and separating the gasoline condensate thereby obtained from the remaining gases under a lpressure materially above atmospheric; subjecting lthe separated gasoline condensate to indirect heat exchange with hot vapors and condensate leaving said highpressure fractionating zone, and condensing and refluxing vnormally liquid constituents thereby vaporized.

8. The process of obtaining gasoline from relatively high-boiling hydrocarbon oil, Which com- 4o prises: heating said oil to a cracking temperature under superatmospheric pressure While in transit through a heating zone; discharging the resultant products into a separating zone and separately removing vapors and residual liquid therefrom; passing at least a portion of said vapors through a high-pressure fractionating zone to effect a condensation of constituents heavier than gasoline; flashing said residual liquid into a low-pressure zone to liberate lower-boiling constituents in vapor form, `and passing the liberated vapors through a relatively low-pressure fractionating zone to condense constituents heavier than gasoline; removing uncondensed vapors from said 10W-pressure fractionating zone, cooling them to effect a condensation of gasoline constituents, and separating gasoline condensate thereby obtained from the gases and vapors remaining uncondensed; compressing said remaining gases and vapors and commingling them With gases and vapors leaving said high-pressure fractionating Zone; cooling said commingled vapors and gases to effect a condensation of gasoline constituents; separating the gasoline condensate thereby obtained from the remaining 65 gases under'a pressure materially above atmospheric; preheating said gasoline condensate by indirect heat exchange With hot vapors from said high-pressure fractionation zone and delivering the preheated gasoline condensate to a 70 second high-pressure fractionating zone; passing hot oil comprising constituents heavier than gasoline from said first-mentioned fractionating zone through said second high-pressure fractionating zone in indirect heat-exchange relation Il pors liberated in said second high-pressure fractionating zone; removing stabilized gasoline from said second high-pressure fractionating zone, and returning said'oil comprising constituents heavier than gasoline to said first-mentioned high-pressure fractionating zone.

9. The process of obtaining gasoline from relatively high-boiling hydrocarbon oil which comprises: heating said oil to a cracking temperature While in transit through a heating zone; discharging the resultant products into a separating zone and separately removing vapors and residual liquid therefrom; passing at least a portion of said vapors through a high-pressure fractionation zone to effect a condensation of constituents heavier than gasoline; iiashing said residual liquid into a zone of lower pressure to liberate lower-boiling constituents in vapor form,

and passing the liberated vapors through a relatively loW pressure fractionation zone to condense constituents heavier than gasoline; removing uncondensed vapors from said 10W-pressure fractionation zone, cooling them to effect a condensation of gasoline constituents, and separating gasoline condensate from the vapors and gases remaining uncondensed in a low pressure separating zone; directing gasoline condensate thus separated into said high pressure fractionation zone to thereby subject it to fractionation therein; compressing said remaining vapors and gases and commingling them under the increased pressure with vapors leaving said high-pressure fractionation zone; cooling the combined vapors and gases under a pressure in excess of that of said low pressure separating zone to effect acondensation of gasoline constituents and separatingr the gasoline condensate thereby obtained from the remaining gases under a pressure materially above atmospheric; and subjecting the separated gasoline condensate to reflux distillation to effect stabilization thereof.

10. The process of obtaining gasoline from relwith gasoline condensate therein; reuxing va-` atively high-boiling hydrocarbonV oll which cornprises: heating said oil to a cracking-"temperature While in transit through a heating zone, discharging the resultant products intora separating zone', and separately 'removing vapors and sA residual liquid therefrom; passing at least a portion of said vapors through a high-presure frac-` tionation zone to effect a condensation of constituents heavier than gasoline, flashing said re'- sidual liquid into a `zone of lower pressure to 10 liberate lower-boiling constituents in vapor form. and passing the liberated vapors through arelatively low-pressure fractionation zonev to condense constituents heavier than gasoline; removing uncondensed vapors fromVV said low-pressure 16 fractionation zone, cooling them to effectV a condensation of gasoline constituents, and separating gasoline condensate 'from the vapors and gases remaining uncondensed in a low pressure separating zone; directing gasoline condensate 20 thus separated into said high pressure fractionation zone to thereby subject it to fractionation therein; compressing said remaining vapors and gases and commingling them under the increased pressure With vapors from said high-pressure fractionation zone; cooling the lcombined vapors and gases under a pressure in excess of that of said low pressure separating zone to effect a condensation of gasoline constituents, and separatingthe gasoline condensate thereby obtained from the remaining gases under a pressure materially above atmospheric; bringing gasoline condensate thus separated into indirect heat exchange With vapors from said high pressure fractonating zone at a point prior to the commingling with said vapors of compressed vapors and gases from the lovv pressure separating zone, directing the gasoline condensate thus heated into a stabilizing zone wherein the gasoline condensate is subjected to reflux distillation to effect stabilization 0 thereof.

VICTOR STAPLETON.

CERTIFICATE or`` CCRRECTICN.

Patent No. 2,026,805, January '7, 1936.

" VICTOR sTAPLEToN.

It is hereby Certified that error appears in the printed specification of the above numbered patent requiring Correction as follows: Page 2., second column, line 45, for "indicating" read indicated; page 4, second column, line 44, claim 3, after "uncondensed" and before the semi-colon insert the words in a low pressure separating zone; line 46, claim 35, after "them" insert the words under the increased pressure; line 48, same claim, after "gases" insert the words under a pressure in excess of that of said low pressure separating zone; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 3rd day of March, A. D. 1936.

Leslie Frazer (Seal) Acting Commissioner of Patents. 

